Another exam question from February 2019, Unit 2104
Q2. Describe the propagation of ferns from spores under EACH of the following headings:
i) collection of spores; 4 marks
ii) sowing media; 2 marks
iii) method of sowing. 4 marks
This question relates to the following part of the syllabus:
Outcome 2. Understand methods of propagation from seeds and spores.
2.3 Describe the propagation of ferns by spores.
To include collection of spores, media used, method of sowing and aftercare.
(NO DETAILS OF LIFE CYCLE REQUIRED)
You can see from the syllabus that the main points from 2.3 are asked for here, although not the aftercare.
For part i) the examiners’ comments suggest the following:
Spores are collected from healthy, true to type plants on a dry day. The spores must be ripe, dark in colour and not empty. Fronds are detached from the parent plant and placed inverted into a clean paper bag or envelope and labelled. Spores are screened and separated from the chaff before placing in an airtight container and stored in dry conditions.
The question asks you to ‘describe’ so expects quite a bit of detail. Although some of the points are very specifically on ferns, several points are more general. These include selecting from healthy, true to type plants, and labelling the bag.
For part ii), the examiners’ comments suggest the following:
It is essential that the sowing media is sterile, e.g. loamless seed sowing media, bark, peat, brick dust or agar gel. The sowing media should be freely textured, free draining and well aerated.
Again, it can be seen that good detail is needed for ‘describe’ – more than just naming a suitable sowing medium.
For part iii), the examiners’ comments suggest the following:
Seed trays or petri dishes must be sterilised before filling them with the sowing media which is consolidated to provide a level surface. The trays are then stood in a tray of sterilised water e.g. distilled water. The spores are sown thinly and evenly on the surface of the sowing media and covered with a sheet of glass or a suitable plastic covering, e.g. clingfilm. All containers must be labelled.
This part is worth 4 marks, and is still ‘describe’ so good detail is required again. It is important to answer this sort of question in a logical way, going through the method step by step. It may be helpful to imagine you are actually carrying out the task while you are writing the answer. Labelling is included again as another general point to include.
One of the most important things to stress for the whole question is that everything needs to be clean and sterile for propagating ferns.